A rump group of House conservatives mounted a quiet revolt Wednesday to seek an across-the-board extension of expiring tax cuts as an alternative to Speaker John A. Boehner’s proposal to extend the cuts just for people with incomes less than $1 million.

The campaign for an amendment to extend all the expiring tax cuts (PL 107-16; PL 108-27) was led by Jim Jordan of Ohio, outgoing chairman of the 164-member conservative Republican Study Committee, and Rep. Mick Mulvaney of South Carolina. The effort had support from other key conservatives, including Steve Scalise of Louisiana, who is in line to be RSC chairman in the 113th Congress. Supporters said they wanted a vote that would affirm the main objectives of many House conservatives, instead of giving ground to Democrats.

GOP aides said Jordan and Mulvaney planned to make the case to the Rules Committee on Wednesday evening to allow a vote on their proposed amendment to the legislative shell bill for Boehner’s proposal, a Burma import restriction measure (H J Res 66).

According to aides, the amendment offered by senior RSC members includes a roster of spending cuts — or sequester replacement measures — to substitute for automatic spending cuts under the 2011 debt deal (PL 112-25).

Party leaders have been vague about whether they would allow conservatives to offer their own across-the-board tax cut extension amendment, noting only that Republicans have previously voted on similar proposals.

Boehner, R-Ohio, and Majority Leader Eric Cantor of Virginia and their team have offered only two potential amendments to the bill, one containing Boehner’s leadership-backed proposal and the other containing a proposal to extend the tax cuts for people with incomes of less than $200,000 and couples with incomes of less than $250,000.

The rump campaign gained momentum after an RSC lunch during which several participants said members had expressed mixed feelings about Boehner’s so-called Plan B proposal to extend the expiring tax cuts for taxpayers with annual earnings less than $1 million.

A participant said Jordan and other conservatives including Mulvaney were lining up behind a proposal to extend all the tax cuts. GOP aides confirmed that Jordan was planning to make a presentation to the Rules Committee. Members said they were getting conflicting feedback from fiscal conservative advocacy groups that were lining up on opposite sides of Boehner’s proposal.

Asked whether he would back Boehner’s Plan B, Scalise declined comment Wednesday afternoon. He said he was pushing for a proposal to extend all the tax cuts.

Jordan has opposed a number of revenue-raising proposals by Boehner, including his opening offer to Obama to raise $800 billion in tax revenue. And he has opposed subsequent revenue-raising proposals by his Ohio colleague.

A number of Republicans said they were undecided, or not yet ready to declare their position on Plan B. “I will make a decision by the end of the day,” said Steve Southerland II of Florida. “I’m not talking,” added Steve Chabot of Ohio.